Implement PrimMesher extrusion geometry (#42)

README.md

@@ -158,5 +158,12 @@ dimensions, strides, and allocations bounded. See
 [`crates/libremetaverse-imaging-skia/README.md`](crates/libremetaverse-imaging-skia/README.md)
 for native prerequisites, cache/source-build controls, licenses, and packaging
 details. Default workspace builds do not compile or link Skia.
+Primitive profile and path meshing is implemented in native Rust from the
+pinned `PrimMesher.cs` reference. It covers checked linear, flexible, and
+circular extrusion; profile cuts and hollows; twist, taper, shear, skew,
+radius, and revolutions; cap and side winding; normals, UVs, viewer faces, and
+prim-face indexing. Geometry allocation and index arithmetic are bounded, and
+identical finite inputs produce deterministic mesh output on every supported
+platform.
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